Bruxism is the nonfunctional gnashing, clenching or grinding of the teeth. Bruxism has been shown to cause or contribute to occlusal tooth wear, increased tooth mobility, tooth loss, bone loss, periodontal disease, muscle pain and spasm. headaches, backaches and temporomandibular joint (TMJ) dysfunction. It can occur nocturnally or diurnally but it is generally believed that this distinction represents two distinct phenomena. Nocturnal bruxism is by far the most serious and difficult to treat since the sufferer is asleep and unaware of grinding behavior.
In order to effectively treat nocturnal bruxism, it is important to understand how and when a bruxing behavior occurs during sleep. Nocturnal bruxism comprises regular repetitive side-to-side tooth contact, which differs markedly from more random patterns which occur during mastication or chewing and swallowing. Bruxism occurs during the lighter stages of sleep, primarily in stage 2 sleep. The termination of bruxism incidents is usually followed by a sleep stage lighter than that before the episodes occurred and never by a deeper sleep stage. Studies have led many researchers to hypothesize that bruxism is a disorder of arousal occurring during the transition from stages 3 and 4 of sleep, to stages 1 and 2.
A number of different treatments for bruxism have been proposed. These treatments include occlusal adjustment (see A. G. Glaros and S. M. Rao, "Bruxism: a Critical Review," Psychological Bulletin, vol. 84, pp. 767-781, 1977; and J. Ahlgren, K. A. Omnell, B. Sonesson and N. G. Toremalm, "Bruxism and Hypertrophy of the Masseter Muscle," Practica Oto-Rhino-Laryngologica, vol. 31, pp. 22-29, 1969); the use of occlusal appliances, such as night guards, and occlusal splints (see Glaros, et al., above) and J. E. Mejias, and N. R. Mehta, "Subjective and Objective Evaluation of Bruxing Patients Undergoing Short-Term Splint Therapy." Journal of Oral Rehabilitation, vol. 9, pp. 279-289, 1982, medication, such as local anesthesia or tranquilizers (see A. I. Chasins, "Methocarbamal (Robaxin) as an Adjunct in the Treatment of Bruxism," Journal of Dental Medicine, vol. 14, pp. 166-178, 1959; and M. A. Goldstein, "Clinical Investigation of Mephate in Dentistry," Dental Digest, vol. 62, p. 454, 1956); massed negative practice (e.g., clenching the teeth while awake to fatigue the jaw muscle) (see W. A. Ayer, "Massed Practice Exercises for the Elimination of Tooth-Grinding Habits," Behavior Research and Therapy, vol. 14, pp. 163-164; 1976; R. F. Heller and A. Forgione, "An Evaluation of Bruxism Control: Massed Negative Practice and Automated Relaxation Training," Journal of Dental Research, vol. 54, pp. 1120-1123, 1975); relaxation therapy (see B. A. Brown, Stress and the Art of Biofeedback, Harper and Row, New York, pp. 82-85, 1977; R. Hamilton, "Battling Bruxism through Biofeedback," TIC, pp. 8-11, May 1986; Heller and Forgione, above; and V. Cornellier, D. M. Keenan and K. Wisser, "The Effects of EMG Biofeedback Training upon Nocturnal and Diurnal Bruxing Responses," International Journal of Orofacial Myology, vol. 8, pp. 11-15, 1982); and aversive conditioning (see W. J. DeRissi, "A Conditioning Approach to the Treatment of Bruxism," PhD Thesis, University of Utah, 1970; R. F. Heller and H. R. Strang, "Controlling Bruxism Through Biofeedback," Behavior Research and Therapy, vol. 11, pp. 327-329, 1973; R. A. Moss, D. Hammer, H. E. Adams, J. O. Jenkins, K. Thompson and J. Haber, "A More Efficient Biofeedback Procedure for the Treatment of Nocturnal Bruxism," Journal of Oral Rehabilitation, vol. 9, pp. 125-131, 1982; G. T. Clark, P. Beemsterboer and J. D. Rugh, "The Treatment of Nocturnal Bruxism using Contingent EMG Feedback with an Arousal Task," Behavior Research and Therapy, vol. 19, pp. 451-455, 1981; A. Piccione, T. J. Coates, J. M. George, D. Rosenthal and P. Karzmark, "Nocturnal Feedback for Nocturnal Bruxism, " Biofeedback and Self Regulation, vol. 7, pp. 405-419, 1982; and M. Cherasia and L. Parks, "Suggestions for the Use of Behavioral Measures in Treating Bruxism." Psychological Reports, vol. 58, pp. 719-722, 1986). Occlusal adjustment and the use of night guards represent dental approaches to treatment and are the outgrowths of mechanical etiology theories. The approach is to eliminate the trigger factors leading to bruxism and to prevent further damage to teeth and soft tissues. Relaxation therapy and medication address the stress that can lead to bruxism, whereas massed negative practice and aversive conditioning are techniques for "unlearning" bruxism behavior. Although varying degrees of success have been reported with all six treatment procedures, aversive conditioning appears to have the most promise.
Because aversive conditioning has been used with great success in treating nocturnal enuresis (bedwetting), whereby a loud buzzer responds as soon as a specially constructed bed pad is moistened by urine (see N. H. Azrin, T. J. Sneed and R. M. Foxx, "Dry Bed Training: Rapid Elimination of Childhood Enuresis," Behavioral Research and Therapy, vol. 12, pp. 147-156, 1974), it is very likely that aversive conditioning can be used to successfully treat bruxism, which like enuresis occurs during lighter stages of sleep. Based upon the results of the treatment of enuresis, it is likely that an extended arousal period would improve aversive conditioning treatment efficiency for bruxism and reduce relapse rates. Most recent treatment recommendations are that treatments for bruxism include (1) an arousal contingency which, for example, requires the patient to wake up and turn off an alarm, (2) an over-correction procedure, which could be, for example, a positive practice such as massaging tense jaw muscles and relaxing and (3) an intermittent consequence schedule, wherein not all bruxing events trigger the alarm, to wean the patient from the treatment (see M. Cherasia, et al , above).
Several U.S. patents disclose devices for determining masticatory, movements U.S. Pat. No. 3,297,021, entitled "Self-Contained Intra Oral Strain Gauge," to Davis, et al., teaches the use of a strain gage sensor mounted with a radio transmitter in a partial denture (false tooth) to determine the forces between the maxilla and mandible. When the patient bites and puts pressure o the false tooth, the strain gage changes capacitance in a way which is proportional to the pressure exerted. The gage is incorporated in a radio transmitter which transmits a radio signal which is proportional to the pressure on the tooth. In this way, pressure is monitored externally. U.S. Pat. No. 4,355,645, entitled "Device for Displaying Masticatory Muscle Activities," to Mitani, et al., teaches the use of an electrode device to determine activities of the masticatory muscles.
U.S. Pat. Nos. 4,169,473 and 4,304,227, to Samelson, are directed to the treatment of snoring and bruxism. The Samelson devices are molded to the upper and lower dental surfaces. The device's engagement with at least one of the user's dental arches is disclosed to eliminate nocturnal tooth grinding. U.S. Pat. No. 4,114,612, to Benjamin discloses a device for relieving muscular tension of the head-neck region of a user. Since symptoms of head-neck tension are said to induce grinding of the teeth (according to this patent), this device is claimed to treat bruxism. U.S. Pat. No. 4,220,142, to Rosen, is a behavior shaping device for eliminating nocturnal sounds such as snoring. An alarm is activated to wake the user when a predetermined level of sound is sensed. It is said that this device can be used to treat bruxism.
The Snore Suppressor, manufactured by Crossley Electronics in Austin, Tex., is primarily marketed as a treatment for snoring, although the manufacturer purports that it will also cure bruxism and sleep apnea. This device is worn as a collar by the patient. Any sound, such as a snore or a tooth grinding sound, causes a tiny electrical impulse to be applied through electrodes that touch each side of the neck. The electric impulse is set low enough so that it does not disturb the sleeper, but allegedly does train the subconscious mind to eliminate snoring (or bruxism). The manufacturer claims an eighty percent cure rate, although this figure appears to be based upon the number of people returning the device under a money back guarantee.
U.S. Pat. No. 4,669,477, entitled "Apparatus and Method for Preventing Bruxism," to Ober, discloses an apparatus for producing an electrical stimulation signal, attached to a patient's jaw muscle, to cause the jaw to open. The electrodes are positioned to sense an electromyographic (EMG) signal indicative of jaw muscle activity and jaw clenching. When bruxism is detected, an electrical stimulation signal is applied to the jaw muscle, thereby causing the jaw to open. Similar devices, sold under the trademarks J-4 and BNS-40 Myo-monitor, are distributed by Myotronics, Inc., of Seattle, Washington. These devices all require the user to wear electrodes attached over the masseter muscles.